document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=17533>Question 17533</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Find all real solutions for x^4-5x^2+4=0 </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #8548 by </B><A HREF=/tutors/aboutme.mpl?userid=xcentaur><B>xcentaur(357)</B></A><img src=\"/images/stars/stars-10.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=xcentaur><IMG SRC=http://www.algebra.com/images/aboutme-small.gif BORDER=0 alt=\"About Me\" VALIGN=MIDDLE></A>&nbsp;<IMG SRC=http://www.algebra.com/images/nopicture.jpg><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=8548\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> x^4-5x^2+4=0<BR>\n" );
document.write( "<br><font color=blue><BR>\n" );
document.write( "Let y=x^2</font><BR>\n" );
document.write( "<br><BR>\n" );
document.write( "Then we get:<BR>\n" );
document.write( "y^2-5y+4=0<BR>\n" );
document.write( "(y-4)(y-1)=0<BR>\n" );
document.write( "Therefore y=4,1<BR>\n" );
document.write( "Therefore x^2=4 or 1<BR>\n" );
document.write( "Since squares of negative numbers are also positive,we get:<BR>\n" );
document.write( "x=+2,-2,+1,-1<BR>\n" );
document.write( "Now out of these,-1 and -2 are both less than zero,ie.non-real<BR>\n" );
document.write( "<br><BR>\n" );
document.write( "Hence real solutions for x will be:<BR>\n" );
document.write( "<font color=blue>x=1,2</font><BR>\n" );
document.write( "<br><BR>\n" );
document.write( "Hope this helps,<BR>\n" );
document.write( "Prabhat </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );